Interpretation:
The observation that cyclohexadecaoctaene isomerizes to two different isomers depending on reaction conditions is to be explained indicating whether each reaction is conrotatory or disrotatory.
Concept introduction:
An electrocyclic reaction involves the cyclization of a conjugated acyclic system. These reactions are reversible and are highly stereospecific.
In elecrocyclic reactions involving even number of electron pairs, a thermal reaction occurs in conrotatory manner and a photochemical reaction occurs in disrotatory manner.
In elecrocyclic reactions involving odd number of electron pairs, a thermal reaction occurs in disrotatory manner and a photochemical reaction occurs in conrotatory manner.
To explain:
The observation that cyclohexadecaoctaene isomerizes to two different isomers depending on reaction conditions.
To indicate:
Whether each reaction is conrotatory or disrotatory.
Trending nowThis is a popular solution!
Chapter 30 Solutions
Organic Chemistry
- Stereoisomers of α-bromocinnamic acid: draw the reaction mechiansim with arows for the dehydrobromination of 2,3-dibromo-3-phenylpropanoic acid with ethanol and KOH to produce (Z)-α-bromocinnamic acid and (E)-α-bromocinnamic acid. Also draw the transition state for The (Z)-isomer syn-periplanar transition state and anti-periplanar transition state of the (E)-isomer.arrow_forwardPredict-the-product. Draw the structure(s) of the major organic profuct(s) formed in the following reactions. Please indicate stereochemistry if appropriate.arrow_forwardGive the structure of the major diastereoisomer formed in the two reactions below. Explain the stereochemical outcome with the aid of Newman projections/transition state diagrams.arrow_forward
- (a) Give a mechanism for this reaction, showing how the two products arise as aconsequence of the resonance-stabilized intermediate.(b) The bromination of cyclohexene using NBS gives only one major product, as shown onthe previous page. Explain why there is no second product from an allylic shift.arrow_forwardThe spirocyclic pentadiene derivative F shown below is converted stereospecificallyinto compound G on heating. The transformation involves two consecutive pericyclicreactions of the same type, and proceeds via compound H which is not isolated. Identify the type of pericyclic reaction occurring, and determine the structure ofcompound H.arrow_forwardFriedel–Crafts alkylation of benzene with (R)-2-chlorobutane and AlCl3 affords sec-butylbenzene.a. How many stereogenic centers are present in the product?b. Would you expect the product to exhibit optical activity? Explain, with reference to the mechanism.arrow_forward
- Although there are nine stereoisomers of 1,2,3,4,5,6hexachlorocyclohexane, one stereoisomer reacts 7000 times more slowly than any of the others in an E2 elimination. Draw the structure of this isomer and explain why this is so.arrow_forward1 Complete the following reaction scheme. Give all product(s) and indicate major or minor and any relevant stereochemistry.arrow_forwardDoxaprost, an orally active bronchodilator patterned after the natural prostaglandins , is synthesized in the following series of reactions starting with ethyl 2-oxocyclopentanecarboxylate. Except for the Nef reaction in Step 8, we have seen examples of all other types of reactions involved in this synthesis. Q. Assuming that the two side chains on the cyclopentanone ring are trans, how many stereoisomers are possible from this synthetic sequence?arrow_forward
- How many stereoisomers are obtained from each of the syntheses describedarrow_forwardFor each one of the following reactions, show step by step mechanism of the reactions and indicate the stereochemistry of the products and their relationshiparrow_forwardIdentify compounds G and H in the following reaction scheme. Hrepresents the structure of stemoamide, the chapter-opening molecule.arrow_forward
- Organic ChemistryChemistryISBN:9781305580350Author:William H. Brown, Brent L. Iverson, Eric Anslyn, Christopher S. FootePublisher:Cengage Learning